CN112852474A

CN112852474A - Refining preheating production line system and method

Info

Publication number: CN112852474A
Application number: CN202110015531.8A
Authority: CN
Inventors: 马哈茂德·巴希耶·马哈茂德·努尔丁; 泽山·法鲁
Original assignee: Saudi Arabian Oil Co
Current assignee: Saudi Arabian Oil Co
Priority date: 2016-05-10
Filing date: 2017-04-19
Publication date: 2021-05-28
Also published as: US10822551B2; US20200048563A1; CN109312235A; EP3455331B1; US10494576B2; SA518400387B1; EP3455331A1; US20170327752A1; WO2017196506A1; CN109312235B

Abstract

A crude oil refining preheat line (PHT) includes: a crude oil stream piping system extending through the PHT and configured to transport a stream of crude oil from an inlet of the PHT to a blast furnace of the PHT; a heat exchanger disposed in the crude oil stream piping system; and a control system. The heat exchanger comprises a first heat exchanger bank disposed in the crude oil stream piping system between the inlet of the PHT and the one or more desalters of the PHT; a second heat exchanger bank disposed in the crude oil stream piping system between the one or more desalters of the PHT and the one or more pre-flash drums of the PHT; and a third heat exchanger bank disposed between the one or more pre-flash tanks of the PHT and the blast furnace of the PHT.

Description

Refining preheating production line system and method

The application is a divisional application of an invention application with the application date of 2017, 4 and 19 months, the international application number of PCT/US2017/028317, the application number of China national phase is 201780038618.9 and the invention name of refining preheating production line system and method.

Cross Reference to Related Applications

This application claims priority from U.S. provisional patent application No. 62/334,095 filed on 10/2016 and U.S. patent application No. 15/444,991 filed on 28/2/2017, both of which are incorporated herein by reference in their entirety.

Technical Field

The present specification relates to a pre-heat train (PHT) system and method for a crude oil refinery.

Background

Refineries are vital to the world's economy and are also the primary energy consumers. Petroleum refineries are under increased pressure to minimize emissions of greenhouse gases, primarily carbon dioxide, to meet upcoming stricter environmental regulations. Energy efficiency optimization is a fast solution for greenhouse gas emission reduction due to its impact on energy consumption at the source.

Generally, heat exchangers play a major role in energy conservation in crude oil refineries. Distillation is the major energy consumer in refineries. Crude oil distillation is a major processing operation in refineries worldwide and requires operational heat, steam and cooling. A Crude Distillation Unit (CDU) consisting of both an atmospheric distillation unit and a vacuum distillation unit is not the most energy intensive unit in a refinery; however, each barrel of crude oil processed in a refinery passes through the CDU in terms of energy usage per unit volume (i.e., energy per barrel processed).

SUMMARY

In a general embodiment according to the present disclosure, a crude oil refinery preheat line (PHT) includes: a crude oil stream piping system extending through the PHT and configured to carry a stream of crude oil from an inlet of the PHT to a blast furnace (also referred to as a furnace) of the PHT; a plurality of heat exchangers disposed in the crude oil stream piping system; and a control system configured to: a first plurality of control valves are actuated to selectively thermally connect the crude oil stream with a plurality of heat sources in a first section of the PHT, a second plurality of control valves are actuated to selectively thermally connect the crude oil stream with a plurality of heat sources in a second section of the PHT, and a third plurality of control valves are actuated to selectively thermally connect the crude oil stream with a plurality of heat sources in a third section of the PHT. The plurality of heat exchangers includes: a first heat exchanger bank disposed in a crude oil stream piping system in a first section of the PHT, the first section including a portion of the PHT between an inlet of the PHT and one or more desalters of the PHT; a second heat exchanger bank disposed in a crude oil stream piping system in a second section of the PHT, the second section including a portion of the PHT after one or more desalters of the PHT and before one or more pre-flash tanks (drum) of the PHT; and a third heat exchanger bank disposed in a crude oil stream piping system in a third section of the PHT, the third section including a portion of the PHT after the one or more pre-flash tanks of the PHT and before a blast furnace of the PHT.

In a first aspect which may be combined with the general embodiment, at least a portion of the plurality of heat exchangers is a shell-and-tube type heat exchanger or a plate-and-frame type heat exchanger.

In another aspect that may be combined with any of the preceding aspects, each of the plurality of heat exchangers includes an adjustable heat exchange surface area.

In another aspect that may be combined with any of the preceding aspects, the first heat exchanger bank disposed in the crude oil stream piping system in the first section of the PHT includes a bank of eight heat exchangers.

In another aspect that may be combined with any of the preceding aspects, a first heat exchanger in the group of eight heat exchangers is configured to thermally connect the crude oil stream with a heavy vacuum unit cold front reflux stream of the PHT; a second heat exchanger in the group of eight heat exchangers is configured to thermally connect the crude oil stream with an atmospheric crude oil tower overhead stream of the PHT; a third heat exchanger in the group of eight heat exchangers is configured to thermally connect the crude oil stream with a crude oil distillation column overhead pumparound (around an overhead pump) stream of the PHT; a fourth heat exchanger in the group of eight heat exchangers is configured to thermally connect the crude oil stream with an atmospheric diesel stream of the PHT; a fifth heat exchanger in the bank of eight heat exchangers is configured to thermally couple the crude oil stream with an atmospheric kerosene stream of the PHT; a sixth heat exchanger in the group of eight heat exchangers is configured to thermally couple the crude oil stream with a naphtha bottoms stream of the PHT; a seventh heat exchanger in the group of eight heat exchangers is configured to thermally connect the crude oil stream with the light vacuum gas oil stream of the PHT; and an eighth heat exchanger in the group of eight heat exchangers is configured to thermally couple the crude oil stream with an atmospheric mid-column pumparound stream of the PHT.

In another aspect that may be combined with any of the preceding aspects, the first, second, and third heat exchangers are arranged in series in the crude oil stream piping system, and the third heat exchanger is arranged in the crude oil stream piping system in series with the fourth through seventh heat exchangers, and the fourth through seventh heat exchangers are arranged in parallel in the crude oil stream piping system, and the eighth heat exchanger is arranged in the crude oil piping system in series with the fourth through seventh heat exchangers.

In another aspect that may be combined with any of the preceding aspects, the second heat exchanger bank disposed in the crude oil stream piping system in the second section of the PHT includes a bank of seven heat exchangers.

In another aspect that may be combined with any of the preceding aspects, a first heat exchanger in the set of seven heat exchangers is configured to thermally couple the crude oil stream with a kerosene product stream of the PHT; a second heat exchanger in the set of seven heat exchangers is configured to thermally connect the crude oil stream with a diesel product stream of the PHT; a third heat exchanger in the set of seven heat exchangers is configured to thermally connect the crude oil stream with the light vacuum gas oil stream of the PHT; a fourth heat exchanger in the set of seven heat exchangers is configured to thermally connect the crude oil stream with a heavy vacuum unit mid pumparound stream of the PHT; a fifth heat exchanger in the set of seven heat exchangers is configured to thermally couple the crude oil stream with the stabilized naphtha stream of the PHT; a sixth heat exchanger in the set of seven heat exchangers is configured to thermally connect the crude oil stream with a crude oil distillation unit mid-pumparound stream of the PHT; and a seventh heat exchanger in the set of seven heat exchangers is configured to thermally connect the crude oil stream with a crude oil distillation unit mid-pumparound stream of the PHT.

In another aspect that may be combined with any of the preceding aspects, the first heat exchanger is disposed in the crude oil stream piping system in parallel with the second heat exchanger, and the second heat exchanger is arranged in the crude oil stream piping system in parallel with the third and fourth heat exchangers, and the third heat exchanger and the fourth heat exchanger are arranged in series in the crude oil stream piping system, and the third and fourth heat exchangers are arranged in the crude oil stream piping system in parallel with the fifth and sixth heat exchangers, and the fifth heat exchanger and the sixth heat exchanger are arranged in series in the crude oil stream piping system, and the seventh heat exchanger is arranged in the crude oil pipeline in series with the first to sixth heat exchangers.

In another aspect that may be combined with any of the preceding aspects, the third heat exchanger bank disposed in the crude oil stream piping system in the third section of the PHT includes a bank of fifteen heat exchangers.

In another aspect that may be combined with any of the preceding aspects, a first heat exchanger in the bank of fifteen heat exchangers is configured to thermally couple the crude oil stream with a heavy vacuum unit mid-cycle reflux of the PHT; a second heat exchanger in the bank of fifteen heat exchangers is configured to thermally connect the crude oil stream with a crude distillation unit mid-pumparound stream of the PHT; a third heat exchanger in the bank of fifteen heat exchangers is configured to thermally connect the crude oil stream with the vacuum residue product stream of the PHT; a fourth heat exchanger in the bank of fifteen heat exchangers is configured to thermally couple the crude oil stream with the kerosene product stream of the PHT; a fifth heat exchanger in the bank of fifteen heat exchangers is configured to thermally connect the crude oil stream with the heavy vacuum gas oil product stream of the PHT; a sixth heat exchanger in the bank of fifteen heat exchangers is configured to thermally connect the crude oil stream with the diesel product stream of the PHT; a seventh heat exchanger in the bank of fifteen heat exchangers is configured to thermally connect the crude oil stream with a heavy vacuum unit lower pumparound stream of the PHT; an eighth heat exchanger in the bank of fifteen heat exchangers is configured to thermally connect the crude oil stream with a heavy vacuum unit lower pumparound stream of the PHT; a ninth heat exchanger in the bank of fifteen heat exchangers is configured to thermally connect the crude oil stream with the vacuum residue product stream of the PHT; a tenth heat exchanger in the bank of fifteen heat exchangers is configured to thermally connect the crude oil stream with the heavy vacuum lower pumparound stream of the PHT; an eleventh heat exchanger in the bank of fifteen heat exchangers is configured to thermally connect the crude oil stream with a crude distillation unit lower pumparound stream of the PHT; a twelfth heat exchanger in the bank of fifteen heat exchangers is configured to thermally connect the crude oil stream with the vacuum residue product stream of the PHT; a thirteenth heat exchanger in the bank of fifteen heat exchangers is configured to thermally connect the crude oil stream with a crude oil distillation unit lower recycle stream of the PHT; a fourteenth heat exchanger in the bank of fifteen heat exchangers is configured to thermally connect the crude oil stream with a hot vacuum stream from a column section feed tank stream of the PHT; and a fifteenth heat exchanger in the bank of fifteen heat exchangers is configured to thermally couple the crude oil stream with the vacuum residue product stream of the PHT.

In another aspect that may be combined with any of the preceding aspects, the first through third heat exchangers are arranged in series in the crude oil stream piping system, and the sixth and seventh heat exchangers are arranged in series in the crude oil stream piping system, and the first through third, fourth, fifth, and sixth through seventh heat exchangers are each arranged in parallel in the crude oil stream piping system.

In another aspect that may be combined with any of the preceding aspects, the eighth heat exchanger is arranged in the crude oil stream piping system in series with the first through seventh heat exchangers, the ninth and tenth heat exchangers are arranged in the crude oil stream piping system in parallel and are also arranged in the crude oil stream piping system in series with the first through eighth heat exchangers, and the eleventh heat exchanger is arranged in the crude oil stream piping system in series with the first through tenth heat exchangers.

In another aspect that may be combined with any of the preceding aspects, the twelfth and thirteenth heat exchangers are arranged in parallel in the crude oil stream piping system, and are also arranged in the crude oil stream piping system in series with the first through eleventh heat exchangers, and each of the fourteenth and fifteenth heat exchangers is arranged in the crude oil stream piping system in series with the first through thirteenth heat exchangers.

In another aspect that may be combined with any of the preceding aspects, the first portion of the plurality of heat exchangers includes a heat exchange surface area that is adjustable from an initial design heat exchange surface area to an adjusted design heat exchange surface area that is 100% to 200% greater than the initial design heat exchange surface area.

In another aspect that may be combined with any of the preceding aspects, the second portion of the plurality of heat exchangers includes a heat exchange surface area adjustable from an initial design heat exchange surface area to an adjusted design heat exchange surface area, the adjusted design heat exchange surface area being 13% to 45% less than the initial design heat exchange surface area.

In another aspect that may be combined with any of the preceding aspects, the third portion of the plurality of heat exchangers includes a heat exchange surface area that is adjustable from an initial design heat exchange surface area to an adjusted design heat exchange surface area that is 20% to 90% greater than the initial design heat exchange surface area.

In another aspect that may be combined with any of the preceding aspects, the fourth portion of the plurality of heat exchangers includes a heat exchange surface area adjustable from an initial design heat exchange surface area to an adjusted design heat exchange surface area that is up to 300% greater than the initial design heat exchange surface area.

In another aspect that may be combined with any of the preceding aspects, each of the plurality of heat exchangers includes a minimum approach temperature that includes a difference between an entry temperature of a hot fluid and an exit temperature of the crude oil stream.

In another aspect that may be combined with any of the preceding aspects, the minimum approach temperature is adjustable between about 30 ℃ and 15 ℃.

In another general embodiment, a method of operating a crude oil refinery preheat line (PHT) includes: circulating a crude oil stream through a crude oil stream piping system extending from an inlet of the PHT through the PHT to a blast furnace of the PHT; circulating the crude oil stream through a plurality of heat exchangers disposed in the crude oil stream piping system; preheating the crude oil stream through the plurality of heat exchangers prior to recycling the preheated crude oil stream to the blast furnace of the PHT; driving a first plurality of control valves with a control system to selectively thermally connect the crude oil stream with a plurality of heat sources in a first section of the PHT; driving a second plurality of control valves with the control system to selectively thermally connect the crude oil stream with a plurality of heat sources in a second section of the PHT; and driving a third plurality of control valves with the control system to selectively thermally connect the crude oil stream with a plurality of heat sources in a third section of the PHT. The plurality of heat exchangers includes: a first heat exchanger bank disposed in a crude oil stream piping system in a first section of the PHT, the first section including a portion of the PHT between an inlet of the PHT and one or more desalters of the PHT; a second heat exchanger bank disposed in a crude oil stream piping system in a second section of the PHT, the second section comprising a portion of the PHT after one or more desalters of the PHT and before one or more pre-flash tanks of the PHT; and a third heat exchanger bank disposed in a crude oil stream piping system in a third section of the PHT, the third section including a portion of the PHT after the one or more pre-flash tanks of the PHT and before a blast furnace of the PHT.

In another aspect that may be combined with any of the preceding aspects, a first heat exchanger in the group of eight heat exchangers thermally couples the crude oil stream with a heavy vacuum unit cold front reflux stream of the PHT; a second heat exchanger in the group of eight heat exchangers thermally couples the crude oil stream with an atmospheric crude tower overhead stream of the PHT; a third heat exchanger in the group of eight heat exchangers thermally couples the crude oil stream to a crude distillation column overhead pumparound (around an overhead pump) stream of the PHT; a fourth heat exchanger in the group of eight heat exchangers thermally couples the crude oil stream with an atmospheric diesel stream of the PHT; a fifth heat exchanger in the bank of eight heat exchangers thermally couples the crude oil stream with an atmospheric kerosene stream of the PHT; a sixth heat exchanger in the group of eight heat exchangers thermally couples the crude oil stream with a naphtha bottoms stream of the PHT; a seventh heat exchanger in the bank of eight heat exchangers thermally couples the crude oil stream with the light vacuum gas oil stream of the PHT; and an eighth heat exchanger in the group of eight heat exchangers thermally couples the crude oil stream with the atmospheric mid-column pumparound stream of the PHT.

In another aspect that may be combined with any of the preceding aspects, a first heat exchanger in the set of seven heat exchangers thermally couples the crude oil stream with the kerosene product stream of the PHT; a second heat exchanger in the set of seven heat exchangers thermally couples the crude oil stream with the diesel product stream of the PHT; a third heat exchanger in the set of seven heat exchangers thermally couples the crude oil stream with the light vacuum gas oil stream of the PHT; a fourth heat exchanger in the set of seven heat exchangers thermally couples the crude oil stream with a heavy vacuum unit mid pumparound stream of the PHT; a fifth heat exchanger in the set of seven heat exchangers thermally couples the crude oil stream with the stabilized naphtha stream of the PHT; a sixth heat exchanger in the set of seven heat exchangers thermally couples the crude oil stream with a crude oil distillation unit mid-pumparound stream of the PHT; and a seventh heat exchanger in the set of seven heat exchangers thermally couples the crude oil stream with a crude oil distillation unit mid-pumparound stream of the PHT.

In another aspect that may be combined with any of the preceding aspects, a first heat exchanger in the bank of fifteen heat exchangers thermally couples the crude oil stream with a heavy vacuum unit mid-cycle reflux of the PHT; a second heat exchanger in the bank of fifteen heat exchangers thermally couples the crude oil stream with a crude oil distillation unit mid-pumparound stream of the PHT; a third heat exchanger in the bank of fifteen heat exchangers thermally couples the crude oil stream with the vacuum residue product stream of the PHT; a fourth heat exchanger in the bank of fifteen heat exchangers thermally couples the crude oil stream with the kerosene product stream of the PHT; a fifth heat exchanger in the bank of fifteen heat exchangers thermally couples the crude oil stream with the heavy vacuum gas oil product stream of the PHT; a sixth heat exchanger in the bank of fifteen heat exchangers thermally couples the crude oil stream with the diesel product stream of the PHT; a seventh heat exchanger in the bank of fifteen heat exchangers thermally couples the crude oil stream with a heavy vacuum unit lower pumparound stream of the PHT; an eighth heat exchanger in the bank of fifteen heat exchangers thermally couples the crude oil stream with a heavy vacuum unit lower pumparound stream of the PHT; a ninth heat exchanger in the bank of fifteen heat exchangers thermally couples the crude oil stream with the vacuum residue product stream of the PHT; a tenth heat exchanger in the bank of fifteen heat exchangers thermally couples the crude oil stream with the heavy vacuum lower pumparound stream of the PHT; an eleventh heat exchanger in the bank of fifteen heat exchangers thermally couples the crude oil stream with a crude distillation unit lower pumparound stream of the PHT; a twelfth heat exchanger in the bank of fifteen heat exchangers thermally couples the crude oil stream with the vacuum residue product stream of the PHT; a thirteenth heat exchanger in the bank of fifteen heat exchangers thermally couples the crude oil stream with a crude oil distillation unit lower recycle stream of the PHT; a fourteenth heat exchanger in the bank of fifteen heat exchangers thermally couples the crude oil stream with a hot vacuum stream from the column section feed tank stream of the PHT; and a fifteenth heat exchanger in the bank of fifteen heat exchangers thermally couples the crude oil stream with the vacuum residue product stream of the PHT.

In another aspect that may be combined with any of the preceding aspects, the first through third heat exchangers are arranged in series in the crude oil stream piping system, and the sixth and seventh heat exchangers are arranged in series in the crude oil stream piping system, and the first through third, fourth, fifth, and sixth through seventh heat exchangers are arranged in parallel in the crude oil stream piping system.

In another aspect that may be combined with any of the preceding aspects, the eighth heat exchanger is disposed in the crude oil stream piping system in series with the first through seventh heat exchangers.

In another aspect that may be combined with any of the preceding aspects, the ninth heat exchanger and tenth heat exchanger are arranged in parallel in the crude oil stream piping system, and are also arranged in series with the first through eighth heat exchangers in the crude oil stream piping system.

In another aspect that may be combined with any of the preceding aspects, the eleventh heat exchanger is arranged in the crude oil stream piping system in series with the first through tenth heat exchangers.

In another aspect that may be combined with any of the preceding aspects, the twelfth and thirteenth heat exchangers are arranged in parallel in the crude oil stream piping system, and are also arranged in series with the first through eleventh heat exchangers in the crude oil stream piping system.

In another aspect that may be combined with any of the preceding aspects, each of the fourteenth and fifteenth heat exchangers is arranged in the crude oil stream piping system in series with the first through thirteenth heat exchangers.

Another aspect that may be combined with any of the preceding aspects, further comprises performing at least one of the following steps: adjusting a heat exchange surface area of a first portion of the plurality of heat exchangers from an initial design heat exchange surface area to an adjusted design heat exchange surface area, the adjusted design heat exchange surface area being 100% to 200% greater than the initial design heat exchange surface area; adjusting a heat exchange surface area of a second portion of the plurality of heat exchangers from an initial design heat exchange surface area to an adjusted design heat exchange surface area, the adjusted design heat exchange surface area being 13% to 45% less than the initial design heat exchange surface area; adjusting a heat exchange surface area of a third portion of the plurality of heat exchangers from an initial design heat exchange surface area to an adjusted design heat exchange surface area, the adjusted design heat exchange surface area being 20% to 90% greater than the initial design heat exchange surface area; or adjusting the heat exchange surface area of a fourth portion of the plurality of heat exchangers from an initial design heat exchange surface area to an adjusted design heat exchange surface area, the adjusted design heat exchange surface area being up to 300% greater than the initial design heat exchange surface area.

Another aspect that may be combined with any of the preceding aspects, further includes adjusting the minimum approach temperature.

In another aspect that may be combined with any of the preceding aspects, adjusting the minimum approach temperature includes adjusting the minimum approach temperature from 30 ℃ to 15 ℃.

Another aspect that may be combined with any of the preceding aspects, further includes adjusting a thermal load of one or more of the plurality of heat exchangers based on adjusting the minimum approach temperature.

In another aspect that may be combined with any of the preceding aspects, adjusting the heat load of one or more of the plurality of heat exchangers includes at least one of: adjusting an amount of heat exchange surface area of one or more of the plurality of heat exchangers; or a material that adjusts the heat exchange surface area of one or more of the plurality of heat exchangers.

In another aspect that may be combined with any of the preceding aspects, adjusting the amount of heat exchange surface area of one or more of the plurality of heat exchangers includes at least one of: adding or removing tubes in one or more of the plurality of heat exchangers; or adding or removing plates in one or more of the plurality of heat exchangers.

Embodiments of crude oil refinery PHTs according to the present disclosure may include one, some, or all of the following features. For example, in a crude blast furnace ahead of an atmospheric distillation tower (which does not have any structural adjustments over refinery life that are manipulated by heat exchanger surface area), embodiments may enable the use of the same technology with minimal energy consumption for medium grade cold crude oil streams and mixed grade crude oil, as compared to conventional PHT systems. Embodiments may enable crude oil refinery operators and owners to formulate future plans for explaining the need for future crude oil distillation unit blast furnaces to debottleneck or energy savings projects, or both. Embodiments of the present disclosure may include exemplary details of PHT design with respect to a minimum approach temperature range of 30 ℃ to 15 ℃ and heat load (Q) of the heat exchanger in megawatts and temperature in degrees celsius. Comparing the energy savings of the embodiments described in this disclosure with the state of the art, the new refinery PHT configuration can achieve fuel savings of about 30 MW. With the described embodiments having more heat exchanger surface area manipulation, this savings can be increased even more up to about 50% to save up to about 50MW of fuel. Given that refineries can operate for about 50 years, the opportunity for missed losses in both fossil fuel savings and greenhouse gas emissions reduction in conventional refinery PHT designs is significant. Also considering that every barrel of oil entering the refinery worldwide passes through the PHT, the worldwide chance of missing in conventional PHT designs can also be significant and increase over time.

The details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.

Brief Description of Drawings

FIGS. 1A-1C are schematic illustrations of a crude oil stream flowing through one or more heat exchangers prior to desalting in a refinery preheat line (PHT).

FIG. 2 is a schematic of a crude oil stream flowing through one or more heat exchangers between desalting and flashing in a refinery PHT.

Fig. 3A-3B are schematic diagrams of a crude oil stream flowing through one or more heat exchangers between a flash and a blast furnace in a refinery PHT.

Fig. 4A-4C are schematic diagrams of a heat exchanger system and heat exchanger sub-system for a crude oil stream flowing in a refinery PHT.

The abbreviations of the drawings and this disclosure include those in table 1:

abbreviations	Description of the invention
		CFR	Cold reflux front
TCR	Top recirculating flow
		MCR	Middle part circulation reflux
LCR	Lower part circulation reflux
		HVGO	Heavy vacuum gas oil
LVGO	Light vacuum gas oil
		CDU	Crude oil distillation unit
HVU	High vacuum unit
		ATM℃OL	Atmospheric tower
V(AC)℃OL	Vacuum tower
		PHT	Preheating production line
Kero	Kerosene oil
		C	Degree centigrade
MW	Megawatt
		Q	Thermal load

TABLE 1

Detailed description of the invention

The present disclosure describes an energy efficient and healthy aging design for a crude oil refinery distillation unit PHT. Embodiments described in this disclosure relate to an energy efficient configuration of an integrated crude atmospheric and vacuum distillation unit PHT. Embodiments described in the present disclosure relate to a preheat sustainable design derived from energy consumption efficiency and fossil fuel based greenhouse gas emissions during the life of a crude oil refinery; for example, by preheating the line heat exchange surface area adjustment. The preheat topology design may be fixed and appropriate from the time the refinery is put into operation until the refinery services are terminated.

Crude oil distillation is a major processing operation in refineries worldwide and requires operational heat, steam and cooling. Although the CDU, which consists of both ADU and VDU, is not the most energy intensive unit in a refinery, each barrel of crude oil processed in a refinery passes through this unit/unit in terms of energy per barrel, making it the largest energy consumer in the total energy consumed in a crude oil refinery.

Crude oil distillation processes separate crude oil into fractions based on their relative boiling points so that downstream processing units/units can be loaded with feedstock that meets specific specifications. For example, a crude oil separation process is accomplished by: crude oil is first fractionated at substantially atmospheric pressure and then a high boiling fraction, referred to as topped crude (grafted crude) or as distilled crude (reduced crude), is fed from the atmospheric distillation column to a second fractionation column operating under vacuum conditions. The crude vacuum distillation unit is used to avoid the high temperatures required to vaporize topped crude at atmospheric pressure. This unit reduces the risk of thermal cracking, product discoloration and fouling of the equipment due to coke formation. The crude oil load is heated to the desired desalting temperature prior to entering the flash zone of the atmospheric distillation tower, desalted, reheated to separate light end vapors in a pre-flash drum or pre-flash tower, and reheated prior to the atmospheric unit blast furnace using a product stream known as reflux recycle (bump arounds) and a tower reflux stream. The desalted and pre-flashed crude oil load was heated to about 375 ℃ in one or more atmospheric distillation furnaces. The topped crude oil from the bottom of the atmospheric tower (sometimes referred to as post-distillate crude oil) is mixed with steam and preheated to about 390 to 450 c before being sent to the vacuum distillation tower. A system using a vacuum pump or a water vapor ejector establishes sub-atmospheric conditions in a vacuum distillation column for separating the high boiling temperature fraction while mitigating heat-induced chemical degradation.

Crude unit designs include PHT. The revamping of crude distillation units including PHT can be performed at least four to five times during the life of the crude refinery, not only due to the need for energy savings, greenhouse gas emissions reduction, but also due to the need for permanent changes in production volume increase, product mix/specification (gasoline over diesel, and vice versa), and API of the processed crude. Since atmospheric and vacuum crude distillation tower designs are highly dependent on the crude unit PHT, any modifications to one system will severely affect each other.

All of these goals result in changing the heat load within the PHT, changing the heat exchanger surface area, changing the pressure drop in the PHT, requiring the addition of new heat exchanger units, requiring changes in unit order, requiring split streams, even requiring new stream matches, requiring changes to the atmospheric or vacuum column internals, requiring changes to the crude oil pump, and other changes. Such a situation may impose a hard constraint on any plant owner to start any revamping, especially on the basis of energy-saving or energy-based reduction of greenhouse gas emissions, unless it is absolutely necessary for debottlenecking of units by blast furnaces to achieve an increase in production. In such situations, there may be opportunities for energy savings and reduction of energy-based greenhouse gas emissions that are ignored.

PHT design improvements in crude units may depend not only on the modification requirements of the PHT, but also on the constraints associated with the distillation column. The interaction between atmospheric and vacuum distillation columns, the intercoolers of the products and conditions of both columns other than the hydraulic case (top pumparound, middle pumparound and bottom pumparound) can create complex problems for the process owners. For any design improvement, this problem may require reconsidering changes based on energy savings alone or emission reduction or both, especially if such changes require long plant downtime when implemented. Such constraints (e.g., downtime for hoisting work, replacement of pipes, or reconfiguration of control equipment) typically allow any crude unit decision maker to completely avoid any attempt to change the PHT design and only consider improvements that primarily employ the original PHT design with minimal changes.

In fact, moving one heat exchanger in a crude unit PHT to a new location to match another stream can be quite difficult, as it requires not only lifting work and downtime, but also more complex engineering work to design the new pipeline structures required and the rack capacity to accommodate the new sections of the pipeline system, including the required PHT to change pipes, civil work, instrumentation and control to improve building material selection, safety research/HAZOP, and other work. In many cases in the PHT area of a crude unit, congestion may not even allow such improvements at all, and if allowed, pipeline configuration improvements may be very expensive. In such a case, reuse of existing heat exchangers, for example at least from the standpoint of the heat exchanger surface area or materials of construction, may be another infeasible situation for consideration of improving PHT energy efficiency.

Adding a new heat exchanger in the PHT to increase the energy efficiency of the crude unit PHT by stream re-matching between the crude cold stream and the hot product, even if advantageous from an energy savings standpoint, may not be feasible due to the aforementioned constraints. In addition, there is no or very little simple way to do this based solely on energy saving benefits. In many other situations, the original design of the PHT may not have any benefit in completing improvements for saving energy and redoing such a design without fully reconsidering the crude unit PHT original design plan. Thus, if the original crude distillation unit PHT design is inappropriate from the outset, the unit owner/operator may be constrained by existing distillation column and PHT design concepts and there may be very limited opportunities to improve PHT energy performance. In other words, the original design may not be changeable at all for energy improvement during its lifetime.

Thus, it may be beneficial for a crude oil refinery to initially design a PHT appropriately (e.g., for optimal energy efficiency over the life of the PHT) to have the ability to capture waste energy without topological improvements to its original design. For example, due to the fact that each barrel of world crude oil passes through a crude distillation unit, a 0.1% reduction in fuel consumption of PHT blast furnaces every day throughout the world, which is a very small energy savings, can be important for both fossil fuel energy consumption reduction in crude oil refineries and fossil fuel-based greenhouse gas emission targets (e.g., about 100,000 barrels of oil equivalent per day (BOE)). Not only in heat exchanger network modifications but also during refinery operational downtime, a large fraction of current crude oil refineries may not be able to achieve 0.1% energy savings in future modification projects with their original PHT design without using significant costs.

The present disclosure describes embodiments of a PHT design configuration for both medium grade and medium-heavy blend grade crudes that avoids the aforementioned problems and minimizes blast furnace fuel consumption over their life. For example, the embodiments may provide a life-healthy aged and energy efficient medium to heavy grade crude unit PHT configuration. In addition, the embodiments may provide a design that is effective for all possible minimum approach temperatures of the PHT heat exchanger between the hot and cold streams. As another example, the embodiments may provide an energy efficient stationary configuration that provides the highest crude unit blast furnace inlet temperature through the addition or bypass of specific heat exchangers in the network, or both.

Embodiments of the PHT design described in this disclosure can provide an energy efficient design that is fixed during the life of the crude oil refinery without any change in its topology, such as reordering of heat exchanger units, re-matching of new units or addition due to energy price increases to enable energy savings during the life of the PHT. In addition to the fouling and scale mitigation methods in current crude unit PHT designs (e.g., chemical methods using additives; solvents, biocides, and chlorinations, or mechanical methods using heat transfer enhancement including tube inserts; spiral baffles, cleaning devices such as abrasives; off-line cleaning), embodiments of the PHT designs described in this disclosure can also have changes in building materials, tube bundle types, or heat exchanger sides (e.g., from shell to tube, and vice versa).

Embodiments of the PHT design described in this disclosure may also include, for example, one or more variable speed pumps after the pre-flash tank, and the new use of additional spare shells (in shell and tube type) or plates (in plate and frame type) or new units from any other heat exchanger unit type. One or more shell or unit locations to be spared in the PHT design may be designated in the heat exchanger before the blast furnace for all types of crude oil being used for processing, or at the parallel heat exchanger before the crude unit blast furnace, depending on the type of crude oil being processed.

Embodiments of the PHT design described in this disclosure may have a fixed crude oil stream path. In an exemplary embodiment, this crude oil path may be divided into three sections. The first section starts from the crude oil inlet of the refinery up to one or more desalters. The second section starts after the desalter to the pre-flash drum/column. The third section starts after the pre-flash tank up to the atmospheric crude furnace. In some embodiments, the third section has two portions: the first section terminates where the entire crude stream passes through a heat exchanger where most fouling begins to accelerate, especially for certain types of crude oils. In some embodiments, the heat load of the heat exchanger along the crude oil stream path may change during the design life, and thus the heat exchanger surface area may also change, but the topology itself (structure) is fixed along the entire PHT.

Heat exchanger

In the configurations described in this disclosure, a heat exchanger is used to transfer heat from one medium (e.g., a stream flowing through a plant in a crude oil refinery PHT, a buffer fluid, or other medium) to another medium (e.g., a crude oil stream flowing through a plant in a crude oil PHT). A heat exchanger is a device that typically transfers heat from a relatively hot fluid stream to a relatively less hot fluid stream. Heat exchangers may be used for heating and cooling applications, such as for refrigerators, air conditioners, or other cooling applications. The heat exchangers may be distinguished from each other based on the direction in which the liquid flows. For example, the heat exchanger may be co-current, cross-current or counter-current. In a parallel flow heat exchanger, the two fluids involved move in the same direction, entering and leaving the heat exchanger side by side. In cross-flow heat exchangers, the fluid paths run perpendicular to each other. In a counter-flow heat exchanger, the fluid paths flow in opposite directions, with one fluid exiting and the other fluid entering. Counter-flow heat exchangers are sometimes more efficient than other types of heat exchangers.

In addition to sorting heat exchangers based on fluid direction, heat exchangers can also be sorted based on their configuration. Some heat exchangers are constructed from multiple tubes. Some heat exchangers include plates having spaces for fluid to flow between them. Some heat exchangers are capable of liquid-to-liquid heat exchange, while some heat exchangers are capable of heat exchange using other media.

Heat exchangers in crude oil refining and petrochemical plants are typically shell and tube type heat exchangers comprising a plurality of tubes through which a liquid flows. The tubes are divided into two groups-the first group containing the liquid to be heated or cooled; the second group contains the liquid responsible for the excitation heat exchange, that is to say the fluid that warms the first group by removing the heat from the tubes of the first group by absorbing and transferring it away or by transferring its own heat inside the liquid. When designing this type of exchanger, care must be taken to determine the appropriate tube wall thickness and tube diameter to allow for optimal heat exchange. The shell and tube heat exchanger may take any of three flow paths for flow.

The heat exchangers in crude oil refining and petrochemical plants may also be plate and frame type heat exchangers. The plate heat exchanger comprises thin plates held by rubber gaskets and joined together with a small amount of space between them. The surface area is large and the corners of each rectangular plate feature openings through which fluid can flow between the plates, extracting heat from the plates as the fluid flows. The fluid channel itself alternates hot and cold liquids, meaning that the heat exchanger can efficiently cool as well as heat the fluid. Because plate heat exchangers have a large surface area, they can sometimes be more efficient than shell and tube heat exchangers. Both the shell-and-plate heat exchangers can be reconfigured over time to adjust (e.g., increase or decrease) their respective heat transfer capacities (i.e., their thermal loads). Such reconfiguration may include, for example, the addition or removal of tubes, a change in tube material, the addition or removal of plates, or a change in plate material, or a combination of changes.

Other types of heat exchangers may include regenerative heat exchangers (also known as regenerative heat exchangers) and adiabatic wheel heat exchangers. In regenerative heat exchangers, the same fluid passes along both sides of the heat exchanger, which may be a plate heat exchanger or a shell and tube heat exchanger. Since the fluid can become very hot, the exiting fluid is used to warm the entering fluid, keeping it near constant temperature. Energy is saved in the regenerative heat exchanger because the process is cyclic, with almost all of the associated heat being transferred from the exiting fluid to the entering fluid. To maintain a constant temperature, a small amount of additional energy is required to raise and lower the overall fluid temperature. In an adiabatic wheel heat exchanger, an intermediate fluid is used to store heat, which is then transferred to the opposite side of the heat exchanger. The adiabatic wheel consists of a large wheel with threads (threads) that rotate through the liquid (both hot and cold) to extract or transfer heat. The heat exchanger described in the present disclosure may include any of the previously described heat exchangers, other heat exchangers, or combinations thereof.

The individual heat exchangers in each configuration may be associated with respective thermal (thermodynamic) loads. The heat duty of a heat exchanger may be defined as the amount of heat that can be transferred by the heat exchanger from a hot stream to a cold stream. The amount of heat can be calculated from the conditions and thermal properties of both the hot and cold streams. From a hot stream perspective, the heat duty of a heat exchanger is the product of the hot stream flow rate, the hot stream specific heat, and the temperature difference between the hot stream inlet temperature into the heat exchanger and the hot stream outlet temperature from the heat exchanger. From the cold stream perspective, the heat duty of the heat exchanger is the product of the cold stream flow rate, the cold stream specific heat, and the temperature difference between the cold stream outlet temperature from the heat exchanger and the cold stream inlet temperature from the heat exchanger. In many applications, it is assumed that there is no loss of heat to the environment for these units, and in particular, in the case of good insulation of these units, these two quantities can be considered to be equal. The heat load of the heat exchanger can be measured in watts (W), Megawatts (MW), million thermal units per hour (Btu/h), or million kilocalories per hour (Kcal/h). In the configuration described herein, the heat load of the heat exchanger is provided as "about X MW", where "X" represents a digital heat load value. The digital thermal load value is not absolute. That is, the actual heat load of the heat exchanger may be approximately equal to X, greater than X, or less than X.

Flow control system

In each of the configurations described later, a process stream (also referred to as a "stream") flows within the crude oil refinery PHT. The process stream may be flowed using one or more flow control systems implemented throughout the crude oil refinery PHT. The flow control system may include one or more pumps for pumping the process stream, one or more flow tubes through which the process stream flows, and one or more valves for regulating the flow of the stream through the tubes.

In some embodiments, the flow control system may be manually operated. For example, an operator may set the flow rate of each pump and set the valve open or closed position to regulate the flow of the process stream through the tubes in the flow control system. Once the operator has set the flow rates and valve open or closed positions of all the flow control systems distributed on the crude oil refinery PHT, the flow control systems can flow streams within the plant or between plants under constant flow conditions, such as constant volumetric rate or other flow conditions. To change the flow conditions, the operator may manually operate the flow control system, for example, by changing the pump flow rate or the valve open or closed position.

In some embodiments, the flow control system may operate automatically. For example, the flow control system may be connected to a computer system to operate the flow control system. The computer system may include a computer-readable medium that stores instructions (e.g., flow control instructions and other instructions) executable by one or more processors to perform operations (e.g., flow control operations). An operator can use a computer system to set the flow rates and valve open or closed positions of all flow control systems distributed throughout the crude oil refinery. In such embodiments, the operator may manually change the flow conditions by providing input via the computer system. Additionally, in such embodiments, the computer system may automatically (i.e., without manual intervention) control one or more of the flow control systems, for example, using a feedback system implemented in one or more devices and connected to the computer system. For example, a sensor (e.g., a pressure sensor, a temperature sensor, or other sensor) may be coupled to a conduit through which the process stream flows. The sensor may monitor and provide a flow condition (e.g., pressure, temperature, or other flow condition) of the process stream to the computing system. The computer system may operate automatically in response to a flow condition that exceeds a threshold value (e.g., a threshold pressure value, a threshold temperature value, or other threshold value). For example, if the pressure or temperature in the conduit exceeds a threshold pressure value or threshold temperature value, respectively, the computer system may provide a signal to the pump to decrease the flow rate, provide a signal to open a valve to release the pressure, provide a signal to close the process stream flow, or provide other signals.

1A-1C, 2, and 3A-3B illustrate a first section 102 (FIGS. 1A-1C), a second section 104 (FIG. 2), and a third section 106 (FIGS. 3A-3B) of a PHT 100 of a crude oil refinery. The PHT 100 shown in these figures and with the accompanying details on the figures, describes a PHT design that begins its lifetime operation at a minimum approach temperature (minimum temperature difference between hot and cold streams) equal to 30 ℃ and moves to half its initial minimum approach temperature, 15 ℃, as its lifetime progresses.

FIGS. 1A-1C are schematic illustrations of a crude oil stream flowing through one or more heat exchangers prior to desalting in a refinery preheat line (PHT) 100. Thus, as previously described, fig. 1A-1C illustrate a crude oil stream path 200 through the first section 102 of the PHT 100, e.g., from a crude oil inlet of a refinery up to one or more desalters. The first section 102 of the PHT includes a heat exchanger network that includes heat exchangers 108a (FIG. 1B), 110a, and 112a (FIG. 1A), and 110B-110e, and 114a (FIG. 1C). The crude oil stream 200 flows through these heat exchangers in the following order: 110a, then 108a, then 112a, then 110b-110e (which are in parallel), then 114 a.

Turning to FIGS. 1A-1B, the crude stream 200 is heated from about 38 ℃ to about 106 and 122 ℃ using the following three hot streams: the heavy vacuum unit cold reflux front in heat exchanger 110 a; the atmospheric crude tower overhead stream in heat exchanger 108a in fig. 1B, and the crude distillation tower overhead reflux stream (around the overhead pump) in heat exchanger 112a (in that order). The thermal load shown in fig. 1A shows the thermal load for heat exchanger 110a and heat exchanger 112a of about 17.4MW and 57MW, respectively, as it progresses over the design life between the beginning of the minimum approach temperature of 30 ℃ and the future stage where the initial minimum approach temperature has halved to 15 ℃.

The thermal load shown in FIG. 1B illustrates the thermal load of approximately 14MW to 37MW of heat exchangers 108a in heat exchanger 108a over the design life of section 102 from the initial start-up of the minimum approach temperature of 30 ℃ to a future stage where the initial minimum approach temperature has halved to 15 ℃.

The atmospheric distillation section in the PHT 100 includes a heat exchanger 108 a. Heat exchanger 108a is used directly in a crude oil stream preheat line design, which is an atmospheric tower overhead vapor stream used to heat a crude oil stream from about 56 ℃ to about 66 ℃ to 82 ℃ at the refinery inlet, using a heat duty of about 14MW to 37 MW. The heat load shown in fig. 1B shows the heat load at a future stage where the initial minimum approach temperature of 30 c to the initial minimum approach temperature has been halved to 15 c.

Crude oil stream 200 in section 102 is split after heat exchanger 112a and circulated in parallel through heat exchangers 110b-110 e. Thus, crude stream 200 is heated from about 106-122 ℃ to 141.5 ℃ by heat exchangers 110b-110e prior to the desalter in FIG. 1C using the following four plus one (4+1) hot streams: an atmospheric diesel stream in heat exchanger 110 b; an atmospheric kerosene stream in heat exchanger 110c, a naphtha bottoms stream in heat exchanger 110d, and a light vacuum gas oil stream in heat exchanger 110 e. The crude oil stream 200 is then combined back into a single stream after heat exchangers 110b-110e and heated by the following fifth stream: reflux is circulated in the middle of the atmospheric tower in heat exchanger 114 a. The thermal loads shown in FIG. 1C illustrate the thermal loads for heat exchangers 110b through 110e of about 6-11MW, 3-6MW, 5-9MW, and 4.5-8 MW. The thermal load shown in FIG. 1C illustrates the thermal load of heat exchanger 114a at about 9-17 MW. These thermal loads are shown along PHT 100 over the design life in section 102 between its initial start-up at an initial minimum approach temperature of 30 ℃ to a future stage where the initial minimum approach temperature has been halved to 15 ℃.

As shown, the crude oil stream 200 is divided into four portions to cool the product from the atmospheric tower in 110b to 110e, where the stream 200 is heated to about 130-135 ℃. The crude oil stream 200 is then sent to a desalter at a temperature of 141.5 ℃, and stream 200 exits the desalting section after desalting at a temperature of 139.5 ℃.

FIG. 2 is a schematic of a crude oil stream 200 flowing through one or more heat exchangers between desalting and flashing in the second section 104 of the PHT 100. As previously mentioned, fig. 2 illustrates a crude oil stream path 200 from one or more desalters to a pre-flash drum/tower. The second section 104 of the PHT 100 includes a heat exchanger network that includes

heat exchangers

116a, 116b, 112c, 114b, 114c, and 116 c. In section 104, crude oil stream 200 flows through heat exchanger 116a, heat exchanger 116a in parallel with heat exchanger 116b, heat exchanger 116b in parallel with a series bank of

heat exchangers

112b and 114b (series), and the series bank of

heat exchangers

112b and 114b in parallel with a series bank of

heat exchangers

112c and 114 c. The crude oil stream 200 then flows through heat exchanger 116 c.

The crude oil stream 200 in fig. 2 after the desalter and before the pre-flash tank was heated from about 139.5 ℃ to about 181.5 ℃ using the following six hot streams: kerosene product in heat exchanger 116 a; diesel product in heat exchanger 116b, light vacuum gas oil in heat exchanger 112b, stabilized naphtha in heat exchanger 112c, heavy vacuum unit mid-cycle reflux in heat exchanger 114b, and crude distillation unit mid-cycle reflux streams in both

heat exchanger units

114c and 116 c.

As shown in FIG. 2, the crude stream 200 is split into three to cool the hot product stream and the reflux stream, wherein the crude stream 200 is heated to about 173-. A stabilized crude stream 200 exits the pre-flash tank from the bottom at about 177 ℃.

The thermal loads shown in FIG. 2 illustrate the thermal loads of the

heat exchangers

112b, 112c, 116a, 116b, 114c, 114b, and 116c of the second section 104, which are about 6-10MW, 7-11MW, 11.1-11.4MW, 6.0-6.2MW, 7-11MW, 6-10MW, and 12-13.6MW, respectively, during its design life between the initial start of the minimum approach temperature of 30 ℃ to a future stage where the initial minimum approach temperature has halved to 15 ℃.

Fig. 3A-3B are schematic diagrams of a crude oil stream flowing through one or more heat exchangers between the flash and the blast furnace in the third section 106 of the refinery PHT 100. 3A-3B illustrate a crude oil stream path 200 from a flash tank/tower to a blast furnace. The third section 106 of the PHT 100 includes a heat exchanger network that includes

heat exchangers

116d, 108b, 116e, 118a, 118b, 118c, 116f, 116g, 116h, 116i, 112d, 112e, 112f, 118d, and 116 j. In section 106, crude oil stream 200 flows through a series bank of

heat exchangers

116d, 108b, and 116e, the series bank of

heat exchangers

116d, 108b, and 116e being in parallel with heat exchanger 118a, the heat exchanger 118a being in parallel with heat exchanger 118b, the heat exchanger 118b also being in parallel with the series bank of

heat exchangers

118c and 116 f. The combined crude stream 200 then flows through heat exchanger 116 g. Crude oil stream 200 is then split and flows through

parallel heat exchangers

116h and 116i, after which it is recombined into a single stream again and flows through heat exchanger 112 d. Crude oil stream 200 is then split again and flows through

parallel heat exchangers

112e and 112f, after which it is again combined into a single stream that flows through

heat exchangers

118d and 116j, before it is introduced into blast furnace 900.

The crude stream 200 after the pre-flash tank in fig. 3A was first split into four sub-streams and heated from 177 ℃ to about 213 ℃. - _ 229 ℃ using the following six hot streams: kerosene product in heat exchanger 118 a; diesel product in heat exchanger 118c, heavy vacuum unit mid-pumparound in heat exchanger 116d, vacuum residuum in heat exchanger 116e, heavy vacuum unit lower pumparound in heat exchanger 116f and crude distillation unit mid-pumparound stream in heat exchanger 108b, and heavy vacuum gas oil product in heat exchanger 118b (part of the heavy vacuum unit mid-pumparound stream). The crude oil stream 200 is then combined into one stream and heated in heat exchanger 116g to about 254 c using the heavy vacuum unit lower pumparound stream coming out of heat exchanger 116 i. The crude oil stream 200 is again split into two sub-streams to heat to about 275 c using the vacuum residue product stream in heat exchanger 116h and the heavy vacuum lower pumparound stream in heat exchanger 116 i. The crude stream 200, now recombined into one stream, is heated in heat exchanger 112d to about 263-283 ℃ using the crude distillation unit lower pumparound stream.

The thermal loads shown in FIG. 3A illustrate thermal loads of approximately 11-14MW, 6.5-9MW, 4.4-6.6MW, 8-14MW, 1-13MW, 23.5MW, 3.7MW, 40MW, 8MW, 26MW, and 13MW for

heat exchangers

116d, 118a, 118b, 118c, 108b, 116e, 116f, 116g, 116h, 116i, and 112d, respectively, over the design life of section 106 between the initial start-up of the minimum approach temperature of 30 deg.C to a future stage where the initial minimum approach temperature has halved to 15 deg.C.

Turning to FIG. 3B, the crude stream at about 266-. The crude oil stream 200 is then heated to about 313 ℃ in

heat exchanger units

118d and 116j, respectively, using the hot vacuum stream and the vacuum residue product stream from the column section feed tank, prior to the atmospheric distillation unit blast furnace. The thermal loads shown in FIG. 3B illustrate that the thermal loads for

heat exchangers

112e, 112f, 118d, and 116j are about 7MW, 14MW, 3MW, and 35MW, respectively, over the design life of section 106 between the initial start-up of the 30 deg.C minimum approach temperature to a future stage where the initial minimum approach temperature has halved to 15 deg.C. The atmospheric crude distillation unit blast furnace load is about 130MW to 160MW within the same minimum approach temperature range.

The atmospheric crude oil blast furnace shown in the PHT 100 can save more fossil fuels and more fuel-based greenhouse gas emissions as the heat exchanger surface area within the heat exchanger network is further manipulated with refinery life advances that can reach 50 years. For example, for medium or mixed grades of crude oil, this PHT 100 can save over 200MM Btu/h and its associated greenhouse gas emissions in 50 years, which the prior art crude oil distillation preheat design for a crude oil refinery with a capacity of 50 ten thousand barrels per day cannot capture or mitigate at all. Given that crude oil is refined over about 9 million barrels per day worldwide in the near future, worldwide fossil fuel savings and fuel-based greenhouse gas emissions are significant using the present invention.

Fig. 4A-4C are schematic diagrams of a heat exchanger system 400 and heat exchanger subsystems for a crude oil stream flowing in a refinery PHT. Generally, these figures illustrate simplified schematic diagrams showing only the crude oil stream and the heat exchangers through which the crude oil stream flows in the previously described PHT 100 of FIGS. 1A-1C, 2 and 3A-3B. In fig. 4A-4C, the heat exchanger network 400 that is part of the PHT is divided into three sections: 405. 410 and 415.

Fig. 4A shows a section 405 of a heat exchanger network 400. In section 405 of the crude stream path, crude stream 420 passes through three heat exchangers (110a, 108a, and 112a) in series, then stream 420 is split into four of the four heat exchangers (110b, 110c, 110d, and 110 e). The crude oil streams 420 are again combined into one stream and the crude oil stream 420 is passed through a heat exchanger (114a) for heating to a desalting temperature. Crude oil exits section 405 and enters section 410 as crude oil stream 425.

Fig. 4B shows a section 410 of the heat exchanger network 400. Section 410 of the crude oil stream path begins after desalting of the crude oil, where crude oil stream 425 is split into two streams. The first crude stream substream is passed through two heat exchangers (116a and 116b) arranged in parallel, after which it is combined with the second substream and passed again in one stream through one heat exchanger (116c) to the pre-flash drum/column. The second crude stream substream passes through two heat exchangers (112b and 114b) arranged in parallel with two other heat exchangers (112c and 114c) arranged in series. The second substream is then combined with the first substream as previously described and exits section 410 as crude stream 430.

Fig. 4C shows section 415 of heat exchanger network 400. The third section 415 of the crude oil path begins after the pre-flash drum/column and consists of two parts. In some embodiments, in the first section, the crude stream 430 exiting the pre-flash drum/tower is pumped (e.g., using one or more variable speed pumps) to effect velocity manipulation of the crude stream 430 in this section of the pre-heat line crude stream path to counter fouling acceleration due to high temperature matching between the crude stream side stream and the product stream and pump around stream (pump around stream).

Crude oil stream 430 splits into three substreams. The first substream passes through three heat exchangers (116d, 108b and 116e) arranged in series, after which it is combined again with two further substreams into a second portion of section 415. The second substream is passed through two heat exchangers (118a and 118b) arranged in parallel. The third substream is passed through two further heat exchangers (118c and 116f) arranged in series.

The three substreams were combined into one stream and passed through a heat exchanger (116 g). This heat exchanger and the heat exchangers downstream thereof may suffer from accelerated fouling due to the high temperature match between the crude oil stream and the product stream as previously described. Fouling mitigation methods may be used, but in the depicted embodiment, design mitigation through three layers may also be used in section 415, depending on the level of fouling expected from the use of a particular crude oil type. The first and permanent layer may be the layer at the last heat exchanger in the PHT before the blast furnace (116j), where the variable speed pump may provide a pressure/velocity increase that moves the fouling particles from the previous heat exchanger to the last heat exchanger. This last heat exchanger (116j) may be designed with additional surface area (e.g., using one or more spare shells) to increase run time before cleaning and allow for an online cleaning method. Second and third layers, which also use spare shells or plates, may be located in parallel-arranged portions of this section 415 and may be used based on crude oil type.

After heat exchanger 116g, crude oil stream 430 is split into two streams and passed through parallel heat exchangers (116h and 116i), and then recombined again into one stream 430 and passed through a single heat exchanger (112 d). Next, crude stream 430 is split again into two streams passing through parallel heat exchangers (112e and 112f) and then recombined again into one stream 430 passing through two heat exchangers (118d and 116j) in series. Crude oil exits section 415 to a blast furnace as crude oil stream 435.

As previously mentioned, the heat exchanger surface area can be adjusted (increased or decreased) over the life of the crude oil refinery PHT. By adjusting the heat exchanger surface area of one or more heat exchangers in the PHT 100, a change in approach temperature may result, heat exchange efficiency may be improved, or the configuration of the PHT 100 may be adjusted while maintaining the designed topology constant over the life of the PHT 100, or any combination thereof.

In some exemplary embodiments, the initial design of a particular heat exchanger in the PHT 100 may have a specified thermal load (e.g., heat transfer capacity), but adjustments to the specified thermal load may also be known at the time of the initial design. For example, one or more of the heat exchangers shown in

sections

102, 104, and 106 of the PHT 100 may have a specified initial capacity and a predetermined (i.e., at initial design time) adjustment to such specified initial capacity. For example, in some embodiments, adjustments may be made according to table 2.

Additionally, in some embodiments, a particular heat exchanger may be designed as a plate and frame type heat exchanger (e.g., as opposed to a shell and tube type or other type of heat exchanger) due to, for example, the amount of increase or decrease in heat exchange surface area operating over life, or due to the amount of initial thermal load. For example, the series of heat exchangers 108, 112, and 118 may be designed as plate and frame type heat exchangers.

TABLE 2

In some embodiments, the 108-series heat exchangers (108a-108b) are fixed in position in the PHT 100 throughout life operation from the initial design (i.e., fixed in terms of topology, configuration, and cold-to-hot stream matching), but are not fixed in terms of heat exchange surface area. The total surface area of each of the heat exchangers 108a-108b may increase from the initial design as the life of the unit elapses to enable the PHT 100 of the crude unit to save more energy in the blast furnace in the future. Additional surface area may be accommodated in the initial heat exchanger unit plan to avoid any future congestion by keeping sufficient floor space for these heat exchangers in the future. The respective surface areas may be gradually increased during each plant retrofit project to improve PHT heat recovery capability, thereby reducing blast furnace fuel consumption. Advantageously, crude oil refinery PHT designers and operators will know the degree of increase needed in the future at the time of initial plant design to reserve some floor space at a particular designated location in the plant for the future.

In some embodiments, the position of the 110-series heat exchangers (110a-110e) in the PHT 100 throughout life operation is fixed from the initial design (that is, fixed in terms of topology, configuration, and cold-to-hot stream matching), and fixed in terms of heat exchange surface area over the life of the device, regardless of the amount of future fuel reduction in the blast furnace. In other words, both the configuration and surface area of these heat exchangers are fixed over the life of the device, even if the PHT 100 is modified in the future to save more energy.

In some embodiments, the 112-series heat exchangers (112a-112f) are fixed in position in the PHT 100 throughout life operation from an initial design (that is, fixed in terms of topology, configuration, and cold-to-hot stream matching), but are not fixed in terms of heat exchange surface area. The total surface area of each of the heat exchangers 112a-112f may increase from the initial design as the life of the unit elapses to enable the PHT 100 of the crude unit to save more energy in the blast furnace in the future. Additional surface area may be accommodated in the initial heat exchanger unit plan to avoid any future congestion by maintaining sufficient future floor space for these heat exchangers. The respective surface areas may be gradually increased during each plant retrofit project to improve PHT heat recovery capability, thereby reducing blast furnace fuel consumption. Advantageously, crude oil refinery PHT designers and operators will know the degree of future increase required at the time of initial plant design to reserve some future floor space at a particular designated location in the plant.

The need for increased surface area of these heat exchangers may be different from unit to unit. For example, a particular 112 series heat exchanger may require a 100% increase in surface area, while another particular 112 series heat exchanger may require a 200% (or more) increase in surface area. In some embodiments, the percentage may be the minimum surface area to be increased and the maximum surface area required to be increased as the life of the device passes for another unit in the 112 series heat exchanger. For example, a 100% increase in a particular 112 series heat exchanger may not necessarily increase during a single retrofit project, but may gradually increase as individual plant retrofit projects to increase PHT heat recovery capability, thereby reducing blast furnace fuel consumption.

In some embodiments, the 114 series heat exchangers (114a-114c) are fixed in position in the PHT 100 throughout life operation from the initial design (i.e., fixed in terms of topology, configuration, and cold-to-hot stream matching), but are not fixed in terms of heat exchange surface area. These 114 series heat exchanger units may not require their respective initial total surface areas to enable the PHT 100 of the crude unit to save more energy in the blast furnace in the future. For example, the additional surface area may be bypassed, or may be some of the tubes or plates inside the heat exchanger removed from the unit to achieve a reduction in heat exchange surface area. The surface area reduction requirements for these heat exchangers may vary from unit to unit. For example, one unit may require a 13% reduction in surface area, while another unit may require a 45% reduction in heat exchange surface area. Advantageously, crude oil refinery PHT designers and operators will know the degree of reduction required in the future at the time of initial plant design to reserve some future floor space at a particular designated location in the plant.

In some embodiments, for another unit in the 114 series heat exchanger, the percentage may be the minimum surface area to be reduced and the maximum surface area to be increased as the life of the device goes by. For example, a 45% reduction in a particular 112 series heat exchanger may not necessarily be reduced during a single retrofit project, but may be gradually reduced at various plant retrofit projects to increase PHT heat recovery capability, thereby reducing blast furnace fuel consumption.

In some embodiments, the 116-series heat exchangers (116a-116j) are fixed in position in the PHT 100 throughout life operation from the initial design (i.e., fixed in terms of topology, configuration, and cold-to-hot stream matching), but are not fixed in terms of heat exchange surface area. The total surface area of each of the heat exchangers 116a-116j may increase from the initial design as the life of the unit elapses to enable the PHT 100 of the crude unit to save more energy in the blast furnace in the future. Additional surface area may be accommodated in the initial heat exchanger unit plan to avoid any future congestion by maintaining sufficient future floor space for these heat exchangers. The respective surface areas may be gradually increased during each plant retrofit project to improve PHT heat recovery capability, thereby reducing blast furnace fuel consumption. Advantageously, crude oil refinery PHT designers and operators will know the degree of future increase required at the time of initial plant design to reserve some future floor space at a particular designated location in the plant.

The increased surface area requirements for these heat exchangers may vary from unit to unit. For example, a particular 116-series heat exchanger may require a 20% surface area increase, while another particular 116-series heat exchanger may require a 90% (or more) surface area increase. In some embodiments, the percentage may be the minimum surface area to be increased and the maximum surface area required to be increased as the life of the device passes for another unit in the series 116 heat exchangers. For example, the 90% increase in a particular 116 series heat exchanger may not necessarily be increased during a single retrofit project, but may be gradually increased as individual plant retrofit projects are performed to increase PHT heat recovery capability to reduce blast furnace fuel consumption.

In some embodiments, the 118-series heat exchangers (118a-118d) are fixed in position in the PHT 100 throughout life operation from the initial design (i.e., fixed in terms of topology, configuration, and cold-to-hot stream matching), but are not fixed in terms of heat exchange surface area. The total surface area of each of the heat exchangers 118a-118d may increase from the initial design as the life of the unit elapses to enable the PHT 100 of the crude unit to save more energy in the blast furnace in the future. Additional surface area may be accommodated in the initial heat exchanger unit plan to avoid any future congestion by maintaining sufficient future floor space for these heat exchangers. The respective surface areas may be gradually increased during each plant retrofit project to improve PHT heat recovery capability, thereby reducing blast furnace fuel consumption. Advantageously, crude oil refinery PHT designers and operators will know the degree of future increase required at the time of initial plant design to reserve some future floor space at a particular designated location in the plant.

The increased surface area requirements for these heat exchangers may vary from unit to unit. For example, a particular 118 series heat exchanger may require 200% surface area increase, while another particular 118 series heat exchanger may require 300% (or more) surface area increase. In some embodiments, the percentage may be the minimum surface area to be increased and the maximum surface area required to be increased over the life of the device for another unit in the 118 series heat exchanger. For example, a 300% increase in a particular 118 series heat exchanger may not necessarily be increased during a single retrofit project, but may be gradually increased as individual plant retrofit projects are performed to increase PHT heat recovery capability to reduce blast furnace fuel consumption.

The reduction or increase in heat exchanger surface area in the PHT 100 fixed topology is due to the new heat transfer heat load (Q) required by the unit when using the adjusted (e.g., lower) value for the minimum approach temperature (e.g., the difference in the incoming temperature of the hot fluid and the outgoing temperature of the crude oil stream 200). In addition, the new waste heat recovery from a particular heat exchanger results in a different Log Mean Temperature Difference (LMTD), which is determined by the following equation:

where A is the heat exchange surface area of the heat exchanger in square meters, Q is the heat load in MW, U is the heat transfer coefficient in watts per square meter per Kelvin, and LMTD is the log mean temperature difference in Kelvin. LMTD may be represented as:

wherein Δ T_AIs the temperature difference between the two fluid streams at the first end "A" of the heat exchanger, and Δ T_BIs the temperature difference between the two fluid streams at the second end "B" of the heat exchanger. These temperature differences correspond, for example, to a particular minimum approach temperature (e.g., from 30 ℃ down to 15 ℃) employed in the PHT 100 at a particular operating point within the total life operation.

Particular embodiments of the present subject matter have been described above. Other embodiments are within the scope of the following claims.

Claims

1. A refining system, comprising:

a hydrocarbon stream piping system extending through the refining system and configured to carry a stream of hydrocarbons from an inlet of the refining system;

a plurality of heat exchangers disposed in the hydrocarbon stream piping system, each of the plurality of heat exchangers comprising an adjustable heat exchange surface area, the plurality of heat exchangers comprising:

a first heat exchanger bank disposed in a hydrocarbon stream piping system in a first reaction or separation section of the refining system, the first reaction or separation section including a portion of the refining system between an inlet of the refining system and a second reaction or separation section of the refining system, the first heat exchanger bank including a first portion of heat exchangers in the first heat exchanger bank disposed in series and a second portion of heat exchangers in the first heat exchanger bank disposed in parallel, and

a second heat exchanger bank disposed in a hydrocarbon stream piping system in a second reaction or separation section of the refining system, the second reaction or separation section comprising a portion of the refining system after the first reaction or separation section of the refining system and before a third separation section of the refining system, the second heat exchanger bank comprising a first portion of heat exchangers of the second heat exchanger bank arranged in series and a second portion of heat exchangers of the second heat exchanger bank arranged in parallel; and

a control system configured to actuate a first plurality of control valves to selectively thermally connect the hydrocarbon stream with a plurality of heat sources of the refining system in a first reaction or separation section within the first heat exchanger bank, the control system further configured to actuate a second plurality of control valves to selectively thermally connect the hydrocarbon stream with a plurality of heat sources of the refining system in a second reaction or separation section within the second heat exchanger bank.

2. The refining system of claim 1, wherein at least a portion of the plurality of heat exchangers is a shell and tube type heat exchanger or a plate and frame type heat exchanger.

3. The refining system of claim 1, wherein:

a first portion of the plurality of heat exchangers includes a heat exchange surface area that is adjustable from an initial design heat exchange surface area to an adjusted design heat exchange surface area that is 100% to 200% greater than the initial design heat exchange surface area;

a second portion of the plurality of heat exchangers includes a heat exchange surface area that is adjustable from an initial design heat exchange surface area to an adjusted design heat exchange surface area that is 13% to 45% less than the initial design heat exchange surface area;

a third portion of the plurality of heat exchangers includes a heat exchange surface area of an adjusted design heat exchange surface area adjustable from an initial design heat exchange surface area to an adjusted design heat exchange surface area that is 20% to 90% greater than the initial design heat exchange surface area; and is

A fourth portion of the plurality of heat exchangers includes a heat exchange surface area of an adjusted design heat exchange surface area adjustable from an initial design heat exchange surface area to an adjusted design heat exchange surface area that is at most 300% greater than the initial design heat exchange surface area.

4. The refining system of claim 1, wherein each of the plurality of heat exchangers includes a minimum approach temperature, the minimum approach temperature including a difference between an entry temperature of a hot fluid and an exit temperature of the hydrocarbon stream.

5. The refining system of claim 4, wherein the minimum approach temperature is adjustable between about 30 ℃ and 15 ℃.

6. The refining system of claim 1, wherein a first portion of the heat exchangers in the first heat exchanger bank disposed in series includes at least three heat exchangers in series, and a second portion of the heat exchangers in the first heat exchanger bank disposed in parallel includes at least four heat exchangers in parallel.

7. The refining system of claim 1, wherein a first portion of the heat exchangers in the second heat exchanger bank, arranged in series, includes at least two heat exchangers in series, and a second portion of the heat exchangers in the second heat exchanger bank, arranged in parallel, includes at least six heat exchangers in parallel.

8. The refining system of claim 6, wherein a first portion of the heat exchangers in the second heat exchanger bank, arranged in series, includes at least two heat exchangers in series, and a second portion of the heat exchangers in the second heat exchanger bank, arranged in parallel, includes at least six heat exchangers in parallel.

9. The refining system of claim 1, wherein the plurality of heat exchangers further includes a third heat exchanger bank disposed in a hydrocarbon stream piping system in a third separation section of the refining system, the third separation section including a portion of the refining system after the second reaction or separation section of the refining system and before an outlet of the refining system, the third heat exchanger bank including a first portion of heat exchangers of the third heat exchanger bank disposed in series and a second portion of heat exchangers of the third heat exchanger bank disposed in parallel.

10. The refining system of claim 9, wherein the control system is further configured to drive a third plurality of control valves to selectively thermally connect the hydrocarbon stream with a plurality of heat sources in a third separation section of the refining system within a third heat exchanger bank.

11. The refining system of claim 9, wherein the first portion of the heat exchangers in the third heat exchanger bank arranged in series includes at least seven heat exchangers in series, and the second portion of the heat exchangers in the third heat exchanger bank arranged in parallel includes at least eight heat exchangers in parallel.

12. A hydrocarbon refining process, the process comprising:

circulating a hydrocarbon stream through a hydrocarbon stream piping system extending through the refining system from an inlet of the refining system;

circulating the hydrocarbon stream through a plurality of heat exchangers arranged in the hydrocarbon stream piping system, each of the plurality of heat exchangers comprising an adjustable heat exchange surface area, the plurality of heat exchangers comprising:

a second heat exchanger bank disposed in a hydrocarbon stream piping system in a second reaction or separation section of the refining system, the second reaction or separation section comprising a portion of the refining system after the first reaction or separation section of the refining system and before a third separation section of the refining system, the second heat exchanger bank comprising a first portion of heat exchangers of the second heat exchanger bank arranged in series and a second portion of heat exchangers of the second heat exchanger bank arranged in parallel;

driving a first plurality of control valves with a control system to selectively thermally connect the hydrocarbon stream with a plurality of heat sources of the refining system in a first reaction or separation section within the first heat exchanger bank;

driving a second plurality of control valves with the control system to selectively thermally connect the hydrocarbon stream with a plurality of heat sources of the refining system in a second reaction or separation section within the second heat exchanger bank; and

heating the hydrocarbon stream by the plurality of heat exchangers.

13. The hydrocarbon refining process of claim 12, wherein at least a portion of the plurality of heat exchangers is a shell and tube type heat exchanger or a plate and frame type heat exchanger.

14. The hydrocarbon refining process of claim 12, wherein:

a third portion of the plurality of heat exchangers includes a heat exchange surface area that is adjustable from an initial design heat exchange surface area to an adjusted design heat exchange surface area that is 20% to 90% greater than the initial design heat exchange surface area; and

a fourth portion of the plurality of heat exchangers includes a heat exchange surface area that is adjustable from an initial design heat exchange surface area to an adjusted design heat exchange surface area that is at most 300% greater than the initial design heat exchange surface area.

15. The hydrocarbon refining process of claim 12, wherein each of the plurality of heat exchangers includes a minimum approach temperature that includes a difference between an entry temperature of a hot fluid and an exit temperature of the hydrocarbon stream.

16. The hydrocarbon refining process of claim 15, wherein the minimum approach temperature is adjustable between about 30 ℃ and 15 ℃.

17. The hydrocarbon refining process of claim 12, wherein a first portion of the heat exchangers in the first heat exchanger bank having heat exchangers arranged in series includes at least three heat exchangers in series, and a second portion of the heat exchangers in the first heat exchanger bank having heat exchangers arranged in parallel includes at least four heat exchangers in parallel.

18. The hydrocarbon refining process of claim 12, wherein a first portion of the heat exchangers in the second heat exchanger bank, arranged in series, comprises at least two heat exchangers in series, and a second portion of the heat exchangers in the second heat exchanger bank, arranged in parallel, comprises at least six heat exchangers in parallel.

19. The hydrocarbon refining process of claim 17, wherein a first portion of the heat exchangers in the second heat exchanger bank, arranged in series, comprises at least two heat exchangers in series, and a second portion of the heat exchangers in the second heat exchanger bank, arranged in parallel, comprises at least six heat exchangers in parallel.

20. The hydrocarbon refining process of claim 12, wherein the plurality of heat exchangers further includes a third heat exchanger bank disposed in a hydrocarbon stream piping system in a third separation section of the refining system, the third separation section including a portion of the refining system after the second reaction or separation section of the refining system and before an outlet of the refining system, the third heat exchanger bank including a first portion of the heat exchangers in the third heat exchanger bank disposed in series and a second portion of the heat exchangers in the third heat exchanger bank disposed in parallel.

21. The hydrocarbon refining process of claim 20, wherein the hydrocarbon refining process further comprises: driving, with the control system, a third plurality of control valves to selectively thermally connect the hydrocarbon stream with a plurality of heat sources in a third separation section of the refining system within a third heat exchanger bank.

22. The hydrocarbon refining process of claim 20, wherein a first portion of the heat exchangers in the third heat exchanger bank arranged in series includes at least seven heat exchangers in series, and a second portion of the heat exchangers in the third heat exchanger bank arranged in parallel includes at least eight heat exchangers in parallel.

23. A refining system, comprising:

a plurality of heat exchangers disposed in the hydrocarbon stream piping system, the plurality of heat exchangers comprising:

a control system configured to actuate a first plurality of control valves to selectively thermally connect the hydrocarbon stream with a plurality of heat sources of the refining system in a first reaction or separation section within a first heat exchanger bank, the control system further configured to actuate a second plurality of control valves to selectively thermally connect the hydrocarbon stream with a plurality of heat sources of the refining system in a second reaction or separation section within a second heat exchanger bank, wherein:

24. A refining system, comprising:

a first heat exchanger bank disposed in a hydrocarbon stream piping system in a first reaction or separation section of the refining system, the first reaction or separation section including a portion of the refining system between an inlet of the refining system and a second reaction or separation section of the refining system, the first heat exchanger bank including a first portion of heat exchangers in the first heat exchanger bank disposed in series and a second portion of heat exchangers in the first heat exchanger bank disposed in parallel, the first portion of heat exchangers in the first heat exchanger bank disposed in series including at least three heat exchangers in series, and the second portion of heat exchangers in the first heat exchanger bank disposed in parallel including at least four heat exchangers in parallel, and

a second heat exchanger bank disposed in a hydrocarbon stream piping system in a second reaction or separation section of the refining system, the second reaction or separation section comprising a portion of the refining system after the first reaction or separation section of the refining system and before a third separation section of the refining system, the second heat exchanger bank comprising a first portion of heat exchangers of the second heat exchanger bank disposed in series and a second portion of heat exchangers of the second heat exchanger bank disposed in parallel; and

25. A refining system, comprising:

a second heat exchanger bank disposed in a hydrocarbon stream piping system in a second reaction or separation section of the refining system, the second reaction or separation section comprises a portion of the refining system after the first reaction or separation section of the refining system and before the third separation section of the refining system, the second heat exchanger group includes a first partial heat exchanger in which heat exchangers in the second heat exchanger group are arranged in series and a second partial heat exchanger in which heat exchangers in the second heat exchanger group are arranged in parallel, the heat exchangers in the second heat exchanger group comprise at least two heat exchangers in series in a first part of the heat exchangers arranged in series, and a second portion of the heat exchangers in the second heat exchanger bank, arranged in parallel, comprises at least six parallel heat exchangers; and

26. A refining system, comprising:

a first heat exchanger bank disposed in a hydrocarbon stream piping system in a first reaction or separation section of the refining system, the first reaction or separation section including a portion of the refining system between an inlet of the refining system and a second reaction or separation section of the refining system, the first heat exchanger bank including a first portion of heat exchangers in the first heat exchanger bank disposed in series and a second portion of heat exchangers in the first heat exchanger bank disposed in parallel,

a second heat exchanger bank disposed in a hydrocarbon stream piping system in a second reaction or separation section of the refining system, the second reaction or separation section comprising a portion of the refining system after the first reaction or separation section of the refining system and before a third separation section of the refining system, the second heat exchanger bank comprising a first portion of heat exchangers of the second heat exchanger bank disposed in series and a second portion of heat exchangers of the second heat exchanger bank disposed in parallel, and

a third heat exchanger bank disposed in a hydrocarbon stream piping system in a third separation section of the refining system, the third separation section including a portion of the refining system after the second reaction or separation section of the refining system and before an outlet of the refining system, the third heat exchanger bank including a first portion of heat exchangers of the third heat exchanger bank disposed in series and a second portion of heat exchangers of the third heat exchanger bank disposed in parallel; and

27. A method of scouring, the method comprising:

circulating the hydrocarbon stream through a plurality of heat exchangers disposed in the hydrocarbon stream piping system, the plurality of heat exchangers comprising:

heating the hydrocarbon stream by the plurality of heat exchangers, wherein:

28. A method of scouring, the method comprising:

heating the hydrocarbon stream by the plurality of heat exchangers.

29. A method of scouring, the method comprising:

a second heat exchanger bank disposed in a hydrocarbon stream piping system in a second reaction or separation section of the refining system, the second reaction or separation section comprises the portion of the refining system after the first reaction or separation section of the refining system and before the third separation section of the refining system, the second heat exchanger group includes a first partial heat exchanger in which heat exchangers in the second heat exchanger group are arranged in series and a second partial heat exchanger in which heat exchangers in the second heat exchanger group are arranged in parallel, the heat exchangers in the second heat exchanger group comprise at least two heat exchangers in series in a first part of the heat exchangers arranged in series, and a second portion of the heat exchangers in the second heat exchanger bank, arranged in parallel, comprises at least six parallel heat exchangers;

heating the hydrocarbon stream by the plurality of heat exchangers.

30. A method of scouring, the method comprising:

a third heat exchanger bank disposed in a hydrocarbon stream piping system in a third separation section of the refining system, the third separation section including a portion of the refining system after the second reaction or separation section of the refining system and before an outlet of the refining system, the third heat exchanger bank including a first portion of heat exchangers of the third heat exchanger bank disposed in series and a second portion of heat exchangers of the third heat exchanger bank disposed in parallel;

heating the hydrocarbon stream by the plurality of heat exchangers.